'\" t
.\"***************************************************************************
.\" Copyright 2018-2022,2022 Thomas E. Dickey                                *
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.\" $Id: curs_mouse.3x,v 1.59 2022/02/12 20:05:11 tom Exp $
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.TH curs_mouse 3X ""
.na
.hy 0
.SH NAME
\fBhas_mouse\fP,
\fBgetmouse\fP, \fBungetmouse\fP,
\fBmousemask\fP, \fBwenclose\fP,
\fBmouse_trafo\fP, \fBwmouse_trafo\fP,
\fBmouseinterval\fP \- mouse interface through curses
.ad
.hy
.SH SYNOPSIS
\fB#include <curses.h>\fP
.PP
\fBtypedef unsigned long mmask_t;\fP
.PP
.nf
\fBtypedef struct {\fP
\fB    short id;         \fI/* ID to distinguish multiple devices */\fR
\fB    int x, y, z;      \fI/* event coordinates */\fR
\fB    mmask_t bstate;   \fI/* button state bits */\fR
\fB} MEVENT;\fP
.fi
.PP
\fBbool has_mouse(void);\fP
.sp
\fBint getmouse(MEVENT *\fIevent\fB);\fR
.br
\fBint ungetmouse(MEVENT *\fIevent\fB);\fR
.sp
\fBmmask_t mousemask(mmask_t \fInewmask\fB, mmask_t *\fIoldmask\fB);\fR
.sp
\fBbool wenclose(const WINDOW *\fIwin\fB, int \fIy\fB, int \fIx\fB);\fR
.sp
\fBbool mouse_trafo(int* \fIpY\fB, int* \fIpX\fB, bool \fIto_screen\fB);\fR
.br
\fBbool wmouse_trafo(const WINDOW* \fIwin\fB,\fR
                  \fBint* \fIpY\fB, int* \fIpX\fB, bool \fIto_screen\fB);\fR
.sp
\fBint mouseinterval(int \fIerval\fB);\fR
.br
.SH DESCRIPTION
These functions provide an interface to mouse events from
\fBncurses\fP(3X).
Mouse events are represented by \fBKEY_MOUSE\fP
pseudo-key values in the \fBwgetch\fP(3X) input stream.
.SS mousemask
.PP
To make mouse events visible, use the \fBmousemask\fP function.
This sets the mouse events to be reported.
By default, no mouse events are reported.
.bP
The function returns an updated copy of \fInewmask\fP
to indicate which of the specified mouse events can be reported.
.IP
If the screen has not been initialized,
or if the terminal does not support mouse-events,
this function returns 0.
.bP
If \fIoldmask\fP is non-NULL,
this function fills the indicated location with the previous value of the
current screen's mouse event mask.
.PP
As a side effect, setting a zero mousemask may turn off the mouse pointer;
setting a nonzero mask may turn it on.
Whether this happens is device-dependent.
.SS Mouse events
.PP
Here are the mouse event type masks which may be defined:
.PP
.TS
l l
_ _
l l.
\fBName\fP	\fBDescription\fP
BUTTON1_PRESSED	mouse button 1 down
BUTTON1_RELEASED	mouse button 1 up
BUTTON1_CLICKED	mouse button 1 clicked
BUTTON1_DOUBLE_CLICKED	mouse button 1 double clicked
BUTTON1_TRIPLE_CLICKED	mouse button 1 triple clicked
_
BUTTON2_PRESSED	mouse button 2 down
BUTTON2_RELEASED	mouse button 2 up
BUTTON2_CLICKED	mouse button 2 clicked
BUTTON2_DOUBLE_CLICKED	mouse button 2 double clicked
BUTTON2_TRIPLE_CLICKED	mouse button 2 triple clicked
_
BUTTON3_PRESSED	mouse button 3 down
BUTTON3_RELEASED	mouse button 3 up
BUTTON3_CLICKED	mouse button 3 clicked
BUTTON3_DOUBLE_CLICKED	mouse button 3 double clicked
BUTTON3_TRIPLE_CLICKED	mouse button 3 triple clicked
_
BUTTON4_PRESSED	mouse button 4 down
BUTTON4_RELEASED	mouse button 4 up
BUTTON4_CLICKED	mouse button 4 clicked
BUTTON4_DOUBLE_CLICKED	mouse button 4 double clicked
BUTTON4_TRIPLE_CLICKED	mouse button 4 triple clicked
_
BUTTON5_PRESSED	mouse button 5 down
BUTTON5_RELEASED	mouse button 5 up
BUTTON5_CLICKED	mouse button 5 clicked
BUTTON5_DOUBLE_CLICKED	mouse button 5 double clicked
BUTTON5_TRIPLE_CLICKED	mouse button 5 triple clicked
_
BUTTON_SHIFT	shift was down during button state change
BUTTON_CTRL	control was down during button state change
BUTTON_ALT	alt was down during button state change
ALL_MOUSE_EVENTS	report all button state changes
REPORT_MOUSE_POSITION	report mouse movement
_
.TE
.SS getmouse
.PP
Once a class of mouse events has been made visible in a window,
calling the \fBwgetch\fP function on that window may return
\fBKEY_MOUSE\fP as an indicator that a mouse event has been queued.
To read the event data and pop the event off the queue, call
\fBgetmouse\fP.
This function will return \fBOK\fP if a mouse event
is actually visible in the given window, \fBERR\fP otherwise.
When \fBgetmouse\fP returns \fBOK\fP, the data deposited as y and
x in the event structure coordinates will be screen-relative character-cell
coordinates.
The returned state mask will have exactly one bit set to
indicate the event type.
The corresponding data in the queue is marked invalid.
A subsequent call to \fBgetmouse\fP will retrieve the next older
item from the queue.
.SS ungetmouse
.PP
The \fBungetmouse\fP function behaves analogously to \fBungetch\fP.
It pushes
a \fBKEY_MOUSE\fP event onto the input queue, and associates with that event
the given state data and screen-relative character-cell coordinates.
.SS wenclose
.PP
The \fBwenclose\fP function tests whether a given pair of screen-relative
character-cell coordinates is enclosed by a given window, returning \fBTRUE\fP
if it is and \fBFALSE\fP otherwise.
It is useful for determining what subset of
the screen windows enclose the location of a mouse event.
.SS wmouse_trafo
.PP
The \fBwmouse_trafo\fP function transforms a given pair of coordinates
from stdscr-relative coordinates
to coordinates relative to the given window or vice versa.
The resulting stdscr-relative coordinates are not always identical
to window-relative coordinates due to the mechanism to reserve lines on top
or bottom of the screen for other purposes
(see the \fBripoffline\fP and \fBslk_init\fP(3X) calls, for example).
.bP
If the parameter \fIto_screen\fP is \fBTRUE\fP, the pointers
\fIpY, pX\fP must reference the coordinates of a location
inside the window \fIwin\fP.
They are converted to window-relative coordinates and returned
through the pointers.
If the conversion was successful, the function returns \fBTRUE\fP.
.bP
If one of the parameters was NULL or the location is
not inside the window, \fBFALSE\fP is returned.
.bP
If \fIto_screen\fP is
\fBFALSE\fP, the pointers \fIpY, pX\fP must reference window-relative
coordinates.
They are converted to stdscr-relative coordinates if the
window \fIwin\fP encloses this point.
In this case the function returns \fBTRUE\fP.
.bP
If one of the parameters is NULL or the point is not inside the
window, \fBFALSE\fP is returned.
The referenced coordinates
are only replaced by the converted coordinates if the transformation was
successful.
.SS mouse_trafo
.PP
The \fBmouse_trafo\fP function performs the same translation
as \fBwmouse_trafo\fP,
using stdscr for \fIwin\fP.
.SS mouseinterval
.PP
The \fBmouseinterval\fP function sets the maximum time (in thousands of a
second) that can elapse between press and release events for them to
be recognized as a click.
Use \fBmouseinterval(0)\fP to disable click resolution.
This function returns the previous interval value.
Use \fBmouseinterval(\-1)\fP to obtain the interval without altering it.
The default is one sixth of a second.
.SS has_mouse
.PP
The \fBhas_mouse\fP function returns \fBTRUE\fP if the mouse driver has been
successfully initialized.
.PP
Note that mouse events will be ignored when input is in cooked mode, and will
cause an error beep when cooked mode is being simulated in a window by a
function such as \fBgetstr\fP that expects a linefeed for input-loop
termination.
.SH RETURN VALUE
\fBgetmouse\fP and \fBungetmouse\fP
return the integer \fBERR\fP upon failure or \fBOK\fP
upon successful completion:
.RS 3
.TP 5
\fBgetmouse\fP
returns an error.
.bP
If no mouse driver was initialized, or
if the mask parameter is zero,
.bP
It returns an error if a mouse event was detected which did not match the
current \fImousemask\fP.
.bP
It also returns an error if no more events remain in the queue.
.TP 5
\fBungetmouse\fP
returns an error if the FIFO is full.
.RE
.PP
\fBmousemask\fP
returns the mask of reportable events.
.PP
\fBmouseinterval\fP
returns the previous interval value, unless
the terminal was not initialized.
In that case, it returns the maximum interval value (166).
.PP
\fBwenclose\fP and \fBwmouse_trafo\fP
are boolean functions returning \fBTRUE\fP or \fBFALSE\fP depending
on their test result.
.SH PORTABILITY
These calls were designed for \fBncurses\fP(3X), and are not found in SVr4
curses, 4.4BSD curses, or any other previous version of curses.
.PP
SVr4 curses had support for the mouse in a variant of \fBxterm\fP(1).
It is mentioned in a few places, but with no supporting documentation:
.bP
the \*(``libcurses\*('' manual page lists functions for this feature
which are prototyped in \fBcurses.h\fP:
.NS
extern int mouse_set(long int);
extern int mouse_on(long int);
extern int mouse_off(long int);
extern int request_mouse_pos(void);
extern int map_button(unsigned long);
extern void wmouse_position(WINDOW *, int *, int *);
extern unsigned long getmouse(void), getbmap(void);
.NE
.bP
the \*(``terminfo\*('' manual page lists capabilities for the feature
.NS
buttons           btns    BT       Number of buttons on the mouse
get_mouse         getm    Gm       Curses should get button events
key_mouse         kmous   Km       0631, Mouse event has occurred
mouse_info        minfo   Mi       Mouse status information
req_mouse_pos     reqmp   RQ       Request mouse position report
.NE
.bP
the interface made assumptions (as does ncurses) about the escape sequences
sent to and received from the terminal.
.IP
For instance
the SVr4 curses library used the \fBget_mouse\fP capability to tell the
terminal which mouse button events it should send,
passing the mouse-button bit-mask to the terminal.
Also, it could ask the terminal
where the mouse was using the \fBreq_mouse_pos\fP capability.
.IP
Those features required a terminal which had been modified to work with curses.
They were not part of the X Consortium's xterm.
.PP
When developing the xterm mouse support for ncurses in September 1995,
Eric Raymond was uninterested in using the same interface due to its
lack of documentation.
Later, in 1998, Mark Hesseling provided support in
PDCurses 2.3 using the SVr4 interface.
PDCurses, however, does not use video terminals,
making it unnecessary to be concerned about compatibility with the
escape sequences.
.PP
The feature macro \fBNCURSES_MOUSE_VERSION\fP is provided so the preprocessor
can be used to test whether these features are present.
If the interface is changed, the value of \fBNCURSES_MOUSE_VERSION\fP will be
incremented.
These values for \fBNCURSES_MOUSE_VERSION\fP may be
specified when configuring ncurses:
.RS 3
.TP 3
1
has definitions for reserved events.
The mask uses 28 bits.
.TP 3
2
adds definitions for button 5,
removes the definitions for reserved events.
The mask uses 29 bits.
.RE
.PP
The order of the \fBMEVENT\fP structure members is not guaranteed.
Additional fields may be added to the structure in the future.
.PP
Under \fBncurses\fP(3X), these calls are implemented using either
xterm's built-in mouse-tracking API or
platform-specific drivers including
.RS 3
.bP
Alessandro Rubini's gpm server
.bP
FreeBSD sysmouse
.bP
OS/2 EMX
.RE
.PP
If you are using an unsupported configuration,
mouse events will not be visible to
\fBncurses\fP(3X) (and the \fBmousemask\fP function will always
return \fB0\fP).
.PP
If the terminfo entry contains a \fBXM\fP string,
this is used in the xterm mouse driver to control the
way the terminal is initialized for mouse operation.
The default, if \fBXM\fP is not found,
corresponds to private mode 1000 of xterm:
.PP
.RS 3
\\E[?1000%?%p1%{1}%=%th%el%;
.RE
.PP
The mouse driver also recognizes a newer xterm private mode 1006, e.g.,
.PP
.RS 3
\\E[?1006;1000%?%p1%{1}%=%th%el%;
.RE
.PP
The \fIz\fP member in the event structure is not presently used.
It is intended
for use with touch screens (which may be pressure-sensitive) or with
3D-mice/trackballs/power gloves.
.PP
The \fBALL_MOUSE_EVENTS\fP class does not include \fBREPORT_MOUSE_POSITION\fP.
They are distinct.
For example, in xterm,
wheel/scrolling mice send position reports as a sequence of
presses of buttons 4 or 5 without matching button-releases.
.SH BUGS
Mouse events under xterm will not in fact be ignored during cooked mode,
if they have been enabled by \fBmousemask\fP.
Instead, the xterm mouse
report sequence will appear in the string read.
.PP
Mouse events under xterm will not be detected correctly in a window with
its keypad bit off, since they are interpreted as a variety of function key.
Your terminfo description should have \fBkmous\fP set to \*(``\\E[M\*(''
(the beginning of the response from xterm for mouse clicks).
Other values for \fBkmous\fP are permitted,
but under the same assumption,
i.e., it is the beginning of the response.
.PP
Because there are no standard terminal responses that would serve to identify
terminals which support the xterm mouse protocol, \fBncurses\fP assumes that
if \fBkmous\fP is defined in the terminal description,
or if the terminal description's primary name or aliases
contain the string \*(``xterm\*('',
then the terminal may send mouse events.
The \fBkmous\fP capability is checked first,
allowing the use of newer xterm mouse protocols
such as xterm's private mode 1006.
.SH SEE ALSO
\fBcurses\fP(3X),
\fBcurs_inopts\fP(3X),
\fBcurs_kernel\fP(3X),
\fBcurs_slk\fP(3X),
\fBcurs_variables\fP(3X).
